Measure the most important reef aquarium levels including calcium, carbonate hardness (KH), phosphate and nitrate with API REEF MASTER TEST KIT. Proper balance is key to the overall health of reef inhabitants. Corals and reef invertebrates like shrimp, crabs and encrusting algae require calcium to grow and proper levels of carbonate hardness to prevent harmful fluctuations in pH. Excess phosphate, which comes from fish waste, uneaten food and other decaying organic matter as well as tap water, can cause algae blooms and affect healthy growth of hard corals. High nitrate levels from fish waste and organic compounds can cause fish disease and algae blooms. The API REEF MASTER TEST KIT comes with four different tests that are specifically calibrated to measure these levels in reef aquariums. Just fill the test tubes, add the test drops and compare results to the color card. Then follow the recommendations on the card if action is required. With API Aquarium products, it?s easy to keep a beautiful saltwater, freshwater or reef aquarium. For over 50 years, API has been creating innovative, research-driven solutions that make it easier to care for your fish and aquarium. API Aquarium Treatment Supplies are designed to work in conjunction with each other to provide best results to control algae, promote healthy bacterial growth and help control and cure fish diseases and conditions such as ich and fin rot. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. With API, you can spend more time admiring your fish, and less time scrubbing your tank. Make sure to use all products as directed in order to ensure the best results.